Improvement in lifting-jacks



. J. 0. JOYCE. Lifting-Jack.

No. 209,344. Patented Oct'. 29, 1878.

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N-FEIERS, PHOTO-LITHOGHAPHER, WASHINGTON. D C.

UNITED STATES. PATENT OEEIoE.

JACOB O. JOYCE, OF DAYTON, OHIO.

IMPROVEMENT lN LIFTING-JACKS.

Specification forming part of Letters Patent No. 209,344, dated October29, 1878; application filed March 14, 1878.

To all whom it may concern- Be it known that I, JACOB O. JOYCE, of

jacks in which the lifting-bar consists of a Screw-spindle turning in anut of the standard. Its object is to adapt this kind of jack to quickwork for railroad and other purposes and it consists substantially inthe herein-described mechanism for substituting for the solid fixed nutof the standard, to wit, segmental movable nuts so arranged that theycan be readily retracted or withdrawn from engagement with thescrew-threads of the lifting-bar, and as readily re-eng aged, in orderthat the said lifting-bar may be quickly adjusted to the height of theweight that is required to be lifted.

In the annexed drawings, Figure 1 is a sec tional elevation of myimproved liftingjack. Fig. 2 is a side elevation thereof. Fig. 3 is adetail view of the segmental nut.

The same letters of reference indicate like parts in all the figures.

The standai d A is tubular, the screw-threaded portion of thelifting-bar B being of a size snugly but not tightly fitting the bore ofthe standard. At the top the standard is provided with two mortises orrecesses, A, for the reception of the segmental nuts 0. In the sidewalls of these mortises oblique slots 0 and c are formed to receivestout pins 0, which project laterally from the upper and lower ends ofthe segmental nuts 0, and serve to hold them in proper position. Theslots 0 and c incline at an angle of forty-five degrees, or thereabout,so that the natural tendency of the segmental nuts is to seek andmaintain the positionin which their pins 0 are in the lower ends ofthese oblique slots. In this position the screw-threads of the segmentalnuts engage the screw-threads of the litting-bar, and the latter may beraised and lowered by screwing, as in an ordinary nut. The length of theslots 0 and c is sufficient to permit a retraction of the segmental nutsuntil they become disengaged from the lifting-bar, when the latter maybe raised or lowered quickly by sliding it up or down, and thus adjustedto the height of the object to be operated upon, and also to rapidlycontract or telescope the jack after use.

The segmental nuts carry pivoted handles D, for convenience ofretracting them. To relieve the pins 0 and c of strain, the arrange mentof the parts may be so calculated that the segmental nuts will touch thebottom of their mortises when they are engaged with the lifting-bar. Thelatter terminates in the usual capstan-head provided with a swivelin gcap.

The working side of the screw-threads, both in the nut and spindle, arein a plane at right angles to the axis of the lifting-bar, while theother side is at an angle thereto of about thirty degrees, the objectbeing that the nuts may be retracted by simply raising the liftingbar byits cap.

What I claim as my invention is- 1. The combination, substantially asspecified, of the screwthreaded lifting-bar, the mortised standardprovided with oblique slots, and the segmental nuts having lateral pinsprojecting into said slots.

2. The lifting-bar provided with beveled screw-threads, in combinationwith the re.-

tractible nuts, as and for the purpose specified.

J. O. J OYGE. Witnesses:

T. H. ORIDLAND, F. I. J oYoE.

